Display screens are the primary visual display interface to a computer. One problem with these visual display screens is that they are limited in size, thus presenting a challenge to user interface design, particularly when larger amounts of information is to be displayed. This problem is normally referred to as the “screen real estate problem”.
Well-known solutions to this problem include panning, zooming, scrolling or combinations thereof. While these solutions are suitable for a large number of visual display applications, these solutions become less effective where the visual information is spatially related, such as maps, newspapers and such like. In this type of information display, panning, zooming and/or scrolling is not as effective as much of the context of the panned, zoomed or scrolled display is hidden.
A recent solution to this problem is the application of “detail-in-context” presentation techniques. Detail-in-context is the magnification of a particular region of interest (the “focal region”) in a data presentation while preserving visibility of the surrounding information. This technique has applicability to the display of large surface area media, such as maps, on limited size computer screens such as personal digital assistants (PDA's) and cell phones.
In the detail-in-context discourse, differentiation is often made between the terms “representation” and “presentation”. A representation is a formal system, or mapping, for specifying raw information or data that is stored in a computer or data processing system. For example, a digital map of a city is a representation of raw data including street names and the relative geographic location of streets and utilities. Such a representation may be displayed visually on computer screen or printed on paper. On the other hand, a presentation is a spatial organization of a given representation that is appropriate for the task at hand. Thus, a presentation of a representation organizes such things as the point of view and the relative emphasis of different parts or regions of the representation. For example, a digital map of a city may be presented with a region magnified to reveal street names.
In general, a detail-in-context presentation may be considered as a distorted view (or distortion) of a portion of the original representation where the distortion is the result of the application of a “lens” like distortion function to the original representation. A detailed review of various detail-in-context presentation techniques such as Elastic Presentation Space (“EPS”) may be found in a publication by Marianne S. T. Carpendale, entitled “A Framework for Elastic Presentation Space” (Burnaby, British Columbia: Simon Fraser University, 1999), and incorporated herein by reference.
Development of increasingly powerful computing devices has lead to new possibilities for applications of detail-in-context viewing. At the same time, the demand for user control over the parameters of a detail-in-context lens has increased. Indeed, one shortcoming of current EPS graphics technology and detail-in-context presentation methods is the lack of an effective user friendly graphical user interface (“GUI”) for the control of lens display parameters. Generally, with a GUI, a user interacts with icons and controls in a GUI display by moving a pointing device, such as a mouse, which causes a censor or pointer to be moved on the display. When the pointer is over the displayed icon or control, the user presses a button, such as a mouse button, to invoke one or more operations to be performed by the computer system.
A GUI for a detail-in-context presentation system is described in Canadian Patent Application No. 2,345,803 filed by the present applicant. However, this GUI does not provide effective zoom functionality.
A need therefore exists for a GUI for a detail-in-context presentation system that has effective zoom functionality. Consequently, it is an object of the present invention to obviate or mitigate at least some of the above-mentioned disadvantages.